Guadiana

The Guadiana River, or Odiana, is an international river defining a long stretch of the Portugal-Spain border, separating Extremadura and Andalucia (Spain) from Alentejo and Algarve (Portugal). The river's basin extends from the eastern portion of Extremadura to the southern provinces of the Algarve; the river and its tributaries flow from east to west, then south through Portugal to the border towns of Vila Real de Santo António (Portugal) and Ayamonte (Spain), where it flows into the Gulf of Cádiz. With a course that covers a distance of 829km, it is the fourth-longest in the Iberian peninsula, and its hydrological basin extends over an area of approximately 68000km2 (the majority of which lies within Spain).EtymologyThe Romans referred to the river as the Flumen Anas, the river of ducks. During the Moorish occupation and settlement, the name was extended and referred to as Wadi Ana, later passed on to Portuguese and Spanish settlers as the Ouadiana, and later just Odiana. Since the 16th century, due to Castilian influences, the name has slowly evolved to take on the form Guadiana, a cognitive variation that developed from many Moorish-Arab river place-names using the prefix guad (such as the rivers Guadalquivir, Guadalete, Guadalajara or Guadarrama).